Aerosolizable Marine Phycotoxins and Human Health Effects: In Vitro Support for the Biogenics Hypothesis
Emmanuel Van Acker,
Maarten De Rijcke,
Jana Asselman,
Ilse M. Beck,
Steve Huysman,
Lynn Vanhaecke,
Karel A.C. De Schamphelaere,
Colin R. Janssen
Affiliations
Emmanuel Van Acker
Laboratory of Environmental Toxicology and Aquatic Ecology, Department of Animal Sciences and Aquatic Ecology, Ghent University, Campus Coupure, Coupure links 653, 9000 Ghent, Belgium
Laboratory of Environmental Toxicology and Aquatic Ecology, Department of Animal Sciences and Aquatic Ecology, Ghent University, Campus Coupure, Coupure links 653, 9000 Ghent, Belgium
Ilse M. Beck
Laboratory for experimental cancer research (LECR), Department for Radiation Oncology and Experimental Cancer Research, Ghent University, Campus UZ, De Pintelaan 185, 9000 Ghent, Belgium
Steve Huysman
Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Campus Merelbeke, Salisburylaan 133, 9820 Merelbeke, Belgium
Lynn Vanhaecke
Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Campus Merelbeke, Salisburylaan 133, 9820 Merelbeke, Belgium
Karel A.C. De Schamphelaere
Laboratory of Environmental Toxicology and Aquatic Ecology, Department of Animal Sciences and Aquatic Ecology, Ghent University, Campus Coupure, Coupure links 653, 9000 Ghent, Belgium
Colin R. Janssen
Laboratory of Environmental Toxicology and Aquatic Ecology, Department of Animal Sciences and Aquatic Ecology, Ghent University, Campus Coupure, Coupure links 653, 9000 Ghent, Belgium
Respiratory exposure to marine phycotoxins is of increasing concern. Inhalation of sea spray aerosols (SSAs), during harmful Karenia brevis and Ostreopsis ovata blooms induces respiratory distress among others. The biogenics hypothesis, however, suggests that regular airborne exposure to natural products is health promoting via a downregulation of the mechanistic target of rapamycin (mTOR) pathway. Until now, little scientific evidence supported this hypothesis. The current explorative in vitro study investigated both health-affecting and potential health-promoting mechanisms of airborne phycotoxin exposure, by analyzing cell viability effects via cytotoxicity assays and effects on the mTOR pathway via western blotting. To that end, A549 and BEAS-2B lung cells were exposed to increasing concentrations (ng·L−1−mg·L−1) of (1) pure phycotoxins and (2) an extract of experimental aerosolized homoyessotoxin (hYTX). The lowest cell viability effect concentrations were found for the examined yessotoxins (YTXs). Contradictory to the other phycotoxins, these YTXs only induced a partial cell viability decrease at the highest test concentrations. Growth inhibition and apoptosis, both linked to mTOR pathway activity, may explain these effects, as both YTXs were shown to downregulate this pathway. This proof-of-principle study supports the biogenics hypothesis, as specific aerosolizable marine products (e.g., YTXs) can downregulate the mTOR pathway.
